The present invention relates to telecommunication systems. More particularly, and not by way of limitation, the present invention is directed to a method and arrangement for monitoring distances among a group of electronic communication devices.
Services that are based on a location, for instance the location of a mobile phone, have recently become more and more popular.
FIG. 1 illustrates a schematic presentation of a communication system comprising a Service Provider (SP) 102 communicating with an Operator 104 over a standardized interface 106. An application 108 at the SP can provide a so called location-based service to a user based on the location of the user. The Operator 104 can include a Location-based Gateway 110 and a Location Enabler 112, which is an entity that can provide the location of the device in point. The Application 108 and the Location-based Gateway 110 may be implemented over a standardized interface as defined by specifications such as Parlay X, Mobile Location Protocol (MLP) etc.
Currently, these standardized specifications comprise three kinds of location-based services:                Get Location: A service for requesting the location of a terminal or a group of terminals;        Notification: A service for raising a notification to a user when a target terminal is entering or leaving a defined location area, or for raising a notification reporting the location of target terminal periodically; and        Get Distance: A service for requesting the distance from a mobile terminal to a fixed location from a service provider.        
The currently existing services are all based on the location of a mobile terminal. They can hence provide information or a notification based on the location of the mobile terminal. It is however a drawback that these existing services are limited to services, which are based on the location of the terminal. Sometimes, there is a demand to base a service on another parameter than the location.
A user may wish to receive information how far it is to one or more friends, colleagues or relatives. Also, a user could appreciate information about whether a group of users have passed a border by either approaching or leaving a neighborhood.